- GET /executions/stale: 장기 실행(stale) 목록 조회
- POST /executions/{id}/abandon: 특정 실행 강제 종료
- POST /executions/stale/abandon-all: stale 일괄 강제 종료
- BatchService에 getStaleExecutions, abandonExecution, abandonAllStale 추가
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>